Pharmacology

STUDY

PLAY

the study of medications and their actions including drug origins, properties and uses. (pg. 204)

Pharmodynamics

study of the interaction of drug molecules with the target cells of living tissue.

Medication Actions

AgonistsSynergistic AgentsAdditive AgentsAtagonists

Agonist

agonistic interaction occurs when a drug potentiates or enhances the effect of another substance.Ex: synergists and additives

Synergistic Agents

Synergists act in combination to produce a stronger or more powerful effect than would be demonstrated if each agent was administed individually.

Additive Agents

Medication additives alter some aspect of the action of the original agent. Example: adding epinephrine to lidocaine

Antagonists

an AGONIST is a medication that binds to a specific receptor site in the body, producing an alteration in biological function and resulting in a desired effect. -an ANTAGONIST binds to the agonist's receptor site, preventing the agonist from binding there and causing it's desired effect.

(Basically, it is a drug that reverses the effects of another drug)pg 205

Therapeutic Action:INDICATIONS

listing of medical conditions that the medication is know to treat pg 205

Therapeutic Action:CONTRAINDICATIONS

list of circumstances or medical conditions under which the medication should not be usedOnset: effects of meds begin showingPeak: effects of meds at peakpg 205

Medication effect:Therapeutic

the concentration or dose of a medication used to produce the desired result without producing a harmful effect

Medication Effect:Side Effect

an expected, undesirable, but tolerable effect of a medication.(ex: dry mouth, constipation, diarrhea, dizziness or drowsiness)

Adverse Effect:

an undesirable and potential harmful effect of a medication that can lead to organ damage or failure.

Toxic Effect

undesirable, unacceptable effects of a medication. can cause CANCER

Drug Effect:Tolerance

reduction in the effect of a medication given at the same dose over a period of time

Addiction

a physical or psychological dependency on the effects of medication

Pharamacokinetics

term to describe entire process of a drug within the body.AbsorptionDistributionBiotransformationExcretionpg 206

Absorption(Pharamacokinetics)

drug must be absorbed to produce an effect.

Distribution(Pharamacokinetics)

involves the transport of the medication within the body once it enters the circulatory system

Biotransformation(Pharamacokinetics)

Biotransformation = metabolism. -mainly broken down in liver

Excretion(Pharamacokinetics)

the effect of medication in the body continues until it is biotransformed or excreted.Kidneys partially responsible for the filtration of medications

PO

Route of AdministrationOral (meaning per os or by mouth) through the GI tract

Route of Administration:Rectal

placed into the rectum

Route of Administration:Intradermal

Between the layers of the skin

SC or SQ

Subcutaneous. Under the skin into the adipose tissue layer

IM

Intramuscular(within the muscle)

IV

Intravenous(into a vein)

Route of Administration:Intra-articular

within a joint

Route of Administration:Intrathecal

Into the subarachnoid space

Route of Administration:Intracardiac

Into the heart

Topical

applied to the skin or mucous membrain

Buccal

medication is placed between the cheek and the teeth until it is dissolved or absorbed

Instillation

Medication is placed in a hollow or cavity

(such as the conjunctival fold or bladder)

Inhalation

medication is directly administered via theRESPIRATORY TRACT

Pg 209Concentration

the concentration of a medication is the ratio of solute to solvent. The two components of a solution

Induction phaseMaintenance phaseEmergence phase (hearing is the last thing to go)Recovery phase

Drug Handling Techniques: pg 212

6 basic rights for correct drug handling

1. The right patient2. The right drug3. The right dose4. The right route of administration5. The right time and frequency6. The right documentation, including labeling

Sellick's maneuver

cricoid pressure

Cricoid Pressure (pg 228)

-performed to reduce the risk of aspiration.-applied prior to induction of anesthesia and continue until the endotracheal tube is placed.-employed in the OR in situations where the patient requires emergency surgery shortly after eating. or the NPO status is not verified, or GI bleeding

Laryngospasm and Bronchospasm(pg 228)

-reactions demonstrated by the lightly anesthetized patient.-a slight trigger of the "gag" reflex results in a spasm or rigidity of the upper respiratory tract....resulting in an inability of the air and waste gases to move in and out of the lungs.-TRIGGERED BY SALIVA IN THE BACK OF THE THROAT

The skeletal muscles are stimulated to contract, but due to the inability of calcium to release, the muscles cannot relax, resulting in rigidity, heat generation, and a buildup of lactic acid and carbon dioxide.

-genetically transmitted disease seen more in males

First sign: unexplained tachycardia (increase in heart rate), followed by tachypnea and an increased level of carbon dioxide.

sodium bicarbonate: to assist in metabolic and respiratory acidosis regulation

dextrose and insulin: to provide available glucose to the cells to maintain cellular metabolism

furosemide or mannitol: to promote renal clearance of waste products

heparin:to prevent intravascular clot formation

Dantrolene

Only pharmacological agent for the treatment of MH-mixed with sterile water-IVANTAGONIST for MH (reverses)

Anesthetic agents:3 categories

inhaltion agentsintravenous agentslocal/regional agents

Inhalation agents(pg 230)

Anesthetic agents that are inhaled and pass into the bloodstream via pulmonary function.

pulmonary function

pertaining to the lungs

oxygen

Inhalation agent:-not an anesthetic agent-essential for survival of the patient...promotes respiration and cellular function

Nitrous oxide

-clear, colorless, fruity odor-only true gas still in use-interacts with the cellular membrane of the CNS to produce ANALGESIA with some amnesia.-eliminated by exhalation-used in conjunction of other anesthetic agents (not strong enough alone)- CONTRAINDICATING its use during some surgical interventions such as tympanoplasty-may contribute to postoperative nausea and vomiting.

It has a pungent aroma, CONTRAINDICATING its use during inhalation induction.-Rapid onset and recovery-not biotransformed in the liver, it is safe to use for patients with hepatic insufficiency-Less expensive than sevoflurane-causes nausea and vomiting like sevoflurane

permit a rapid and pleasant transition from consciousness (Stage 1) to unconsciousness (Stage 3) by quickly passing through the delirium stage (Stage 2)

-Side effects: Hypotension and respiratory depression- may also be used during maintenance of general anesthesiaDrugs: Propofol, Etomidate, Thiopental sodium, Methohexital sodium

Propofol

(Diprivan)

"Milk of amnesia"-sedative-hypnotic agent-discarded within 6 hrs of opening-irritating to the vein and may cause patient discomfort at the IV site(Lidocaine given IV just prior to propofol inj. may ease that discomfort)

-Rapid induction and emergence without the prolonged "hangover" effect

-CONTRAINDICATED: for patients with unstable hemodynamics or head trauma.

Etomidate

(Amidate)

nonbarbiturate hypnotic agent used for anesthesia induction-similar to propofol, but does not produce analgesia

-Leaves patient with a residual hangover effect lasting through and prolonging the patient's emergence and recovery phases.

ADVANTAGES: -marked respiratory and circulatory depression immediately following injection, non flammability, inability to cause irritation to the respiratory tree, and lack of salivary stimulation-Helps reduce Laryngospasm and Bronchospasm due to decreasing saliva

DISADVANTAGES:-minor patient stimulation during the lighter stages of anesthesia administration, which may cause laryngospasm, and the alkaline nature of the drug, which may be locally irritating to the vein.

Halogenated anesthetic agents

considered triggering agents for malignant hypothermia

DISSOCIATIVE AGENTS(pg 231)

Advantage: selectively interrupt the associative pathways of the brain. Patients may appear wide awake, yet they are unaware of their surroundings.-Produce amnesia and profound analgesia.

the first of the synthetic narcotic analgesics to be used for anesthesia administration.

-use with patients with myasthenia gravis is contraindicated

Sufentanil citrate

(Sufenta)similar to fentanyl, but five times more potent-produces analgesia-respiratory depressant-has a rapid onset of action when given IV-It has a short duration of activity and is rapidly eliminated

Alfentanil hydrochloride

(Alfenta)similar in action and usage to fentanyl-short acting analgesic

Disadvantage: induced respiratory depression may outlast the analgesic effect produced

The opioid effect can be antagonized or reversed by the administration of naloxone hydrochloride (Narcan)

Benzodiazeprines(pg 232)

sedative tranquilizers2 ways:-to reduce the anxiety and apprehension of the preoperative patient -as an adjunct to general anesthesia to reduce the amount and concentration of anther more potent agents